Quote4. Create uImage with embedded DTB for booting with older u-boots (2012 or earlier). Do not do this step if you have installed the latest U-Boot for Kirkwood (or are installing this u-boot at the same time).

2. Plug in the USB rootfs to the USB 2.0 port. Power up, interrupt serial console at count down, and

Note: your current envs are set to boot OpenWrt and has some different partitioning layout for NAND. So if you ever want to boot OpenWrt again, there is a little more envs modification to make that happens (more so than I thought before). If you only want to boot Debian, then the above 2 fw_setenv are all you need.

Pretty safe to upgrade kernel. But it's good practice to back up before upgrade. 3 files need to be backed up so you can go back to the current kernel: your uImage, uInitrd, and dts/kirkwood-nsa325.dtb files. Or backup the whole /boot folder.

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